Takbir

 

The Takbīr or Tekbir (تَکْبِیر) is the Arabic term for the phrase Allāhu Akbar (الله أکبر). It is usually translated "God is [the] Greatest," or "God is Great". It is a common Islamic Arabic expression. It is used in various contexts by Muslims: in formal prayer, as an informal expression of faith, in times of distress, to express celebration or victory, and to express resolute determination or defiance. 

 http://en.wikipedia.org/wiki/Takbir